- Date
- April 28, 1989, 10:30 local (14:30 UTC)
- Place
- Herkimer, NY
- Injuries
- 1 fatal
- Damage
- Destroyed
- Phase of flight
- Enroute
- Aircraft
- N2113UBrantly Helicopter B-2
- Weather
- Visual (VMC) · Day
- Status
- Completed · report June 22, 1992
- Report
- Approved by Office Director
- FAA report
- 19890428010569A
- Case key
- 36284
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
A forced landing in unsuitable terrain due to an internal engine failure. The engine failure sequence was initiated by a failed oil pressure relief spring which had failed in fatigue due to improper plating of the spring. The spring failure caused oil starvation to the engine crankshaft and resulting failure of a connecting rod.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
The aircraft was found in a wooded area about 1-1/2 miles north of the departure heliport. On-scene investigation revealed a hole in the engine case near cylinder #4. A later engine teardown showed that the #4 connecting rod had failed at the crankshaft journal. The journal displayed typical discoloration and scoring from overheating and a lack of lubrication. The oil pressure relief valve spring, p/n 68668, was broken into 3 pieces. Metallurgical exam revealed that the spring failed in fatigue which probably originated from pre-existing cracks developed as a result of hydrogen embrittlement. The general condition of the cadmium plating on the spring was very poor, and plating is not called out in the engineering drawing.
Aircraft
- Registration
- N2113U
- Reported as
- Brantly Helicopter B-2
- Category
- Helicopter
- Serial number
- 161
- Airframe hours
- 897
- Engine
- Lycoming VO 360, 180 horsepower, reciprocating
- Damage
- Destroyed
- Flight
- Personal · Part 91
- Registered owner
- Francis A. Dejohn
- Airworthiness certificate
- Standard, Normal
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 74
- Certificate
- Commercial
- Airplane ratings
- Single-engine sea
- Medical
- Class 3, Valid Medical--no waivers/lim.
- Seat
- Right
- Toxicology
- Performed
Weather
- Conditions
- Visual (VMC) · Day
- Lowest ceiling
- None
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.